1. Field of Invention
The present invention relates to a liquid crystal display device designed to reduce power consumption, to a driving circuit, to a driving method, and to electronic devices.
2. Description of Related Art
In recent years, liquid crystal display devices (LCD) have been widely used for various information processing devices, flat-screen TVs, and other apparatus as display devices to replace cathode ray tubes (CRT).
These liquid crystal display devices can be classified into various types depending on the driving method and other features. An active-matrix-type LCD device, in which pixels are driven by switching elements, is arranged as follows. Specifically, an active-matrix-type LCD device includes pixel electrodes arranged in a matrix, an element substrate provided with switching elements connected to each of the pixel electrodes, a counter substrate on which counter electrodes are formed to face the pixel electrodes, and liquid crystal sandwiched between these substrates.
In this arrangement, when an on-voltage is applied to a scanning line, the switching element connected to the scanning line becomes conductive. In the conductive state, if the voltage signal corresponding to a gray scale (density) is applied to an element electrode via a data line, the charge corresponding to the voltage signal is stored in a liquid crystal capacitor for the liquid crystals sandwiched between the pixel electrode and the counter electrode. After the charge is stored, even if an off-voltage is applied to the scanning line to make the switching element nonconductive, the charge stored in the liquid crystal capacitor is maintained by the capacitance of the liquid crystal capacitor itself, and the accompanying storage capacitor. In this way, by driving each switching element and controlling the amount of charge to be stored according to the gray scale, the orientation of the liquid crystal changes. Thus, the gray level is changed for every pixel, thereby making it possible to perform gray-scale display.
Low power consumption is a favorable feature for liquid crystal devices because of the characteristics, features, and applications of the electronic devices that incorporate liquid crystal devices. At the same time, in order to drive a liquid crystal capacitor, a high voltage swing, such as 10 volts or more, for example, is required. Thus the voltage signal applied to a data line is required to have a similar voltage swing.